Shown below is a venn diagram representing the number of people in music class who play different instruments.

Find the probability that a guitarist selected at random is also a pianist.

$\frac{3}{5}$

The correct answer is Option (3) → $\frac{3}{5}$ ##

Given, $n(\text{pianist} \cap \text{guitarist}) = 33$, $n(\text{guitarist}) = 55$

Finds the probability that a guitarist selected at random is also a pianist as:

$P(\text{pianist} | \text{guitarist}) = \frac{P(\text{pianist} \cap \text{guitarist})}{P(\text{guitarist})}$

$= \frac{33}{55} = \frac{3}{5}$